Engineering heterologous hosts for the production and study of fungal lignin-degrading enzymes
Abstract/Contents
- Abstract
- Lignin is the second-most abundant biopolymer on Earth and has significant potential as a renewable source for commodity chemicals yet remains vastly underutilized. The lack of an established route to lignin deconstruction means that the primary value of industrial lignin by-products is heat and electricity by incineration. Molecular decomposition of lignin would yield derivatives with economic value in chemical and material applications typically reliant on petroleum. Biological catabolism of lignin by wood-decaying basidiomycete fungi is widespread in nature and presents scalable and renewable means of its deconstruction under mild conditions. However, basidiomycete fungi remain genetically intractable and challenging to cultivate rapidly, limiting their utility in the industrial production of lignin-degrading enzymes. Efficient heterologous production of basidiomycete lignin-degrading enzymes has also proven elusive, hampering efforts toward engineering a biochemical route to the valorization of lignin. In this dissertation, I present efforts aimed at overcoming this major obstacle in the field of lignin degradation. I demonstrate that, despite extensive optimization, the model yeast host Saccharomyces cerevisiae is unable to produce most of the lignin-degrading enzymes tested, especially the main agents of fungal lignin degradation, heme peroxidases. In contrast, the model plant host Nicotiana benthamiana natively produces heme peroxidases for cell wall biogenesis, and I found that this host is well-suited for heterologous production of fungal lignin-degrading peroxidases as well as the majority of lignin-degrading enzymes tested. This approach enabled assay of these enzymes in different combinations on a model lignin dimer, revealing different modes of action. Finally, I describe identification of two null mutants of S. cerevisiae that exhibit increased secretion of multiple fungal lignin-degrading peroxidases. This work represents a significant advance in the development of a biochemical route to lignin valorization, with implications for the understanding of biological lignin degradation as well as of factors required for successful production of proteins in heterologous hosts
Description
| Type of resource | text |
|---|---|
| Form | electronic resource; remote; computer; online resource |
| Extent | 1 online resource |
| Place | California |
| Place | [Stanford, California] |
| Publisher | [Stanford University] |
| Copyright date | 2020; ©2020 |
| Publication date | 2020; 2020 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Author | Khlystov, Nikita Andreevich |
|---|---|
| Degree supervisor | Sattely, Elizabeth |
| Thesis advisor | Sattely, Elizabeth |
| Thesis advisor | Khosla, Chaitan, 1964- |
| Thesis advisor | Smolke, Christina D |
| Degree committee member | Khosla, Chaitan, 1964- |
| Degree committee member | Smolke, Christina D |
| Associated with | Stanford University, Department of Chemical Engineering. |
Subjects
| Genre | Theses |
|---|---|
| Genre | Text |
Bibliographic information
| Statement of responsibility | Nikita Andreevich Khlystov |
|---|---|
| Note | Submitted to the Department of Chemical Engineering |
| Thesis | Thesis Ph.D. Stanford University 2020 |
| Location | electronic resource |
Access conditions
- Copyright
- © 2020 by Nikita Andreevich Khlystov
Also listed in
Loading usage metrics...